I apologize for not being able to post the ISO comparisons in the Nikon D750 review earlier today. Unfortunately, the comparisons took a long time, because I had to retest everything several times. My first copy of the D610 had strange exposure issues, making it hard to properly compare it with the D750, so I had to find another one. Just in case, I also got a D600, a D4 and a D4s from Tom Redd (thanks Tom!) to add to the comparison. Since the D4 produced very similar result as my Nikon Df, I did not bother with uploading D4 crops.
After hours of going back and forth trying to figure out why I was seeing strange differences between cameras, I realized that Adobe’s RAW engine (DNG Converter 8.7.0 Beta) was yet again to blame for the inconsistencies and bad RAW rendering. I ended up switching to Capture NX-D 1.0.3 for RAW conversion, which proved to be a much better tool for proper RAW data analysis and comparisons. Basically, I was seeing the same problems in Adobe RAW conversion as I had seen when comparing the Nikon D810 with the D800E. I am not sure why Adobe uses such a bad RAW converter for the new Nikon DSLRs. Sadly, even the final release of ACR and Lightroom 5.6 still had the same buggy RAW converter engine.
The resulting study might be of interest to our readers – the D750 proved to be overall the best Nikon DSLR in terms of noise handling at high ISOs. It outperformed pretty much every DSLR, including the Nikon Df! The Nikon D4s was a bit better at very high ISOs, but come on, who shoots at ISO 51200? How did Nikon do that? Well, if you read my notes, the lower noise is achieved by a few tricks in Nikon’s image processing pipeline. Basically, Nikon is applying a smart curve to images, making shadows appear a bit darker, then applying a more aggressive noise reduction algorithm on top of it. The result is reduced chroma noise in the shadows, making images appear between 1/2 to 2/3 stops better. Take a look at the below comparison between the Nikon D750 and the Nikon D600 / D610 at ISO 12800:
That’s a pretty big difference of noise levels in the shadows!
To see more comparisons of these cameras at both low and high ISOs, along with comparisons to the Nikon D810, Df and D4s, see the Camera Comparisons page of my Nikon D750 review.